1. Field of the Invention
The present invention relates to an internal combustion engine, and more particularly to an exhaust valve and intake system for an internal combustion engine.
2. Description of the Background Art
Only four types of engines have been applied on large scale in the history of engines, including the four stroke engine, the two stroke engine, the Wankel engine, and the gas turbine. Although other engines and power sources like the electric engine, the steam engine, the Stirling engine and fuel-cells are available, the actual level of their development does not allow these alternatives to adequately compete with the internal combustion engines described hereinabove because of the excessive production costs, inefficiency or low functionality.
In the 1970s, the gas turbine seemed able to replace the classic four stroke engine in automotive applications, owing to the gas turbine's simplicity and relatively narrow dimensions. Further, in aeronautical applications, the gas turbine engine has proven to have a better efficiency than alternatives, demonstrated little vibration, operated relatively clean, and was relatively durable and powerful. On the other hand, the acceptable efficiency could be reached only with very high temperatures in the combustion chamber, so it was necessary to build the turbine with special materials, too expensive for a large scale production in automotive applications. Not even the Wankel has been capable of replacing the four stroke engine, even though it had similar prerogatives of the gas turbine without the prohibitive costs of construction, operation and maintenance. Even in this case, the chronic high consumption in addition to a reliability that was possible only recently have invalidated the complete success of the Wankel engine. Although the Wankel engine is still used in those applications in which the fuel consumption is a secondary parameter.
In contrast, the two stroke engine until a few years ago had a plurality of defects, i.e., including, but not limited to high fuel consumption, excessive emissions, irregular functioning at low rpm or idle speeds. However, the latest developments in two stroke engines show highly respectable efficiency and functionality, dimensions that are almost half the size for the same power output. Accordingly, there has been an increase in the motivation of designers to utilize two stroke engines in lieu of four stroke engines. Particularly, the two stroke diesel with the controllable opening of the exhaust system, or in hybrid applications an electric engine coupled with a small alternative internal combustion engine that works constantly at maximum rpm, are able to demonstrate good efficiency. However, these last alternatives are more expensive due to the added costs of the electric engine.
It is obvious that to obtain substantial evolution from an engine it is necessary to operate on various design parameters. For example, a reduction of more possible losses from the exhaust is desired, and/or a reduction in the wastes of the irradiation of heat, because the thermal rendering of alternative endothermal engines is very modest. Efficiency improvement at all rpm and at all the requests of power, e.g., at the maximum couple rpm, the internal friction of engines allows efficiencies of 0.8, but at moderate charges and rpm only a modest 0.55 of efficiency can be achieved. This assumes huge importance, if it is considered that in a life of a vehicle the engine is operated at 80% of capacity at the partial charges and low rpm.
Correct combustion in order to obtain benefits not only in terms of consumption and performances, but also for a reduction of emissions is also desired. An increase in engine versatility, the optimum would be to have the possibility to use the prime mover in different sectors, in the aeronautical fields, in the automotive field, and/or in the nautical field, etc.
The present inventor foresees an engine with total modularity of the block and of the heads, in order to have ample choice of power. Simplicity of the engine, that has no needs of complex or expensive working process nor precious materials. Easy maintenance, assembling and disassembling is desired along with an engine that is light and compact. The combination of some ideas, right after exposed, make possible to realize a new engine design that allows a concentration in the engine all the prerogatives and the improvements cited before, in a simple and compact structure, included in a block substantially cylindrical.